1. Field of the Invention
The present invention relates to an image sensing apparatus for sensing a subject image.
2. Description of the Prior Art
When taking a picture with a camera, the photographer performs framing before releasing the shutter. Framing is important because the quality of the taken picture largely depends on whether framing is appropriately made or not.
At a normal photographing distance, since the area within the finder field frame is always taken on the film, the photographic range is decided with reference to the finder field frame. In short-range photographing, the photographic range is decided with reference to a parallax correction frame provided in the finder. The parallax correction frame is provided for correcting the parallax amount which increases in short-range photographing. In addition to such a camera, a camera is known which is, although high in cost, structured so that the parallax correction frame moves in accordance with the distance measurement result. In this camera, the photographic range is decided with reference to the correction frame that moves.
It is also important in framing to set a composition where the subject is not backlighted. However, more and more cameras have recently been designed so as to compensate for exposure by detecting that the subject is backlighted. Therefore, it has become unnecessary for the photographer to be aware of the position of the sun.
As a cause of failure in releasing the shutter, camera shake is considered. Cameras embodying various ideas to prevent camera shake have previously been known. For example, there is a camera having a function of compensating for camera shake by moving the optical system in accordance with the camera shake amount. According to such a camera, failures caused by camera shake can be reduced although this camera is large in size and high is cost.
However, even in cameras embodying various ideas as described above, taken pictures can be failures. The following are examples of causes of such failures: A beginner sometimes takes pictures without noticing that a part of the subject is situated outside the field frame. In the case of a single-lens reflex camera, although no parallax is caused, there are cases where the photographer does not notice that a part of the subject is situated outside because his or her attention is caught by other operations.
When photographing is performed in a macro mode with a camera having a macro mode capable of short-range photographing at a photographing distance of 40 to 50 cm, although the camera has a parallax correction frame for the macro mode, there are cases where the photographer forgets the presence of the correction frame during photographing and an upper part of the subject (in the case of photographing in landscape orientation) is situated outside. With respect to the lower part of the subject, although even a part not seen in the finder is included in the photographic range, there is no means for confirming it and the photographer cannot help but depend on experience. Consequently, there are cases where the photographer cannot set a composition which he or she desires.
Even if a camera shake compensating function is provided, since this function is limited, the taken pictures can be blurred according to photographing conditions. For example, when a child is photographed, if the child moves when the shutter is released, the taken picture is a failure according to the shutter speed. Further, zoom lens systems have recently become the norm, and particularly, on the telephoto side in compact cameras, the F number of the lens increases and the shutter speed is controlled so as to increase the exposure time, so that the possibility that the taken picture is blurred is high.
Moreover, the backlight correction is also limited. Correction cannot be made when a bright point light source is present within the photographic range and when a light source is situated outside in the vicinity of the finder field, so that there are cases that flare is caused in the taken picture. In the case of compact cameras, since the taking lens and the finder optical system are different, it is difficult to grasp how much the influence of backlight is, so that there are cases where the taken picture is a failure. Since whether the taken picture is failure or not cannot be found until the picture is developed and printed, it is impossible to photograph the subject again on the spot.